Here are my 3, what are yours?
- Merge servers into Mega Servers - This would bring back more of a community that WoW has lost since TBC
- Remove Queable raids and dungeons - This would further improve community by forcing players to group up and interact on their server
- Item Squish (down to TBC Levels) - Almost EVERYONE agrees this is in the best interest of the game going forward.
There very well could be more, but these are the 3 that I think would make the most impact and wouldn't take much for Blizzard to do.